Will there be a Poor Man's GO DJ Version 2?

[admin]

So the original Poor Man's Go DJ has already been through 1 player upgrade.

It still works, and I still use it exclusively when I provide Sound/DJ for local events. While scrolling through the directory listing sometimes causes that module to pause or glitch, the PM GO DJ overall hasn't let me down or even been the cause of any unintended silence for quite a while.

Never the less, I continue to surf various vendors for player modules that would add more actual DJ functionality to a possible new version of the Poor Man's Go DJ. For the first time, I can say that I may have stumbled on a module that's worth investigating.

UPDATE: Please scroll down for a review of a very similar module.

New Module_01.png (168.78 KiB) Viewed 12058 times

A single vendor is selling this module on Aliexpress. I haven't found it for sale, or even mentioned anyplace else.

New Module_02.png (163.28 KiB) Viewed 12058 times

One thing very compelling about this module is that it seems to have a waveform display. It also has at least a progress bar.
Here are a few other things to note about this board:

• The button board can be left attached, or separated from the player module. Not the more full complement of buttons. (See more about buttons, below)
• It also includes 2 encoders mounted on separate boards that connect to the player board (although it does not come with knobs). The encoders have several functions, and may allow fast scrolling through directories/song lists.
• The other connectors (USB, SD Card Slot, 2 Line inputs, etc.) are also on separate boards, allowing flexible mounting options.
• It plays all the formats, including 16 bit FLAC.
• The listing indicates "Working Current 30 - 150 mA" depending on operating state, which is far better than the modules in the current version of the Poor Man's GO DJ.
• It does not seem to do other functions like Photos or Video, indicating more emphasis on Audio Functionality.
• It looks like it may have been intended for a stand-alone Hi-Fi Player or "Digital Turn Table" based on layout, and completed devices that seem to have a similar layout for the buttons and display.
• Upon watching the video again, it does not seem to show the Wave form Display in USB (or SD) player mode. A workaround for this is to simply use 2 for each "Deck or Turntable", with the 2nd one permanently set to Line in, and doing nothing except for displaying the wave form. Given the $20.00 cost of the module, this is not unreasonable at all. The lower part of the 2nd display may need to be covered so there are not 2 spectrum displays on the same player.

With the very limited information in a single listing (Which includes a very short video), there is a lot I cannot tell, including:

• Do the buttons or one of the encoders allow seeking or Fast Forward within a track?
• Can it show time remaining or time-in-track?
• How smooth is it? Does scrolling slow or become "glitchy" with thousands of songs on an SD card?
• "English" is briefly seen in the menus during the video, but the user does not select English language.

At this point, I would not try another module swap in the existing GO DJ. I would begin construction of a Version 2 PM Go DJ.
What features would this new player have?

• Separate Microphone channels. In total it would have 4 separate channels, Each with it's own proper linear level control.
• Each channel would have separate analog tone boards, with the Mic inputs also having a reverb pot and possibly a pan pot. I'd like to have compression on the mic inputs, but I have not found a mic board with that functionality. Note that most of the Chinese Mic boards have (2) 1/4" jacks, so it will actually support 4 microphones.
• I will use proper stereo faders/level pots wired correctly, so that there is no sound from the faded out channel.
• The headphone Live/Cue mix will also be implemented properly, with a separate Headphone amp module driving the 1/4" headphone jack.
• I will either forgo the battery completely, or include a larger 10,000 maH battery (Yes, that means I will destroy another phone charger)
• An internal Power supply with a standard IEC power connector is a possibility -- especially of I forgo the internal battery. If there is an internal PS, it will be a pre-made audio grade +/- power supply.
• As mentioned, the possibility of a separate wave form display for each player. (Not for the Mic inputs).
• It will include an output LED VU meter. A level meter for each mic may or may not be included.
• I will possibly remove and not use the included button boards. Instead, USB mini shortcut keyboards will be destroyed re-wired as simple button to ground. This will allow far nicer and more durable operation.
• It will also include a separate sample player as the current PM GO DJ has. I will do the same thing with (2)4 or a single 8 button PC shortcut keyboard(s) so that the samples are played with mechanical keys. The sample player will have just a regular pot for level control, and no tone board. It will have an LED that shows when it is playing a sample.
• With all of the above, the unit will be much larger than even a GO DJ plus. It will be more like a Poor Man's Denon DJ Prime 4.
• It will likely have a steel or aluminum top panel. It's possible that the base will be made of wood since wood is easy to work with, and it will likely be too large and heavy for the thin plexiglass that is readily available to me.
• It probably will still not have XLR mic inputs nor balanced XLR outputs.

For right now, I intend to buy some of theses or similar player modules for evaluation.

Note that given all of the above, I would likely have as much into this project as I would a used Denon DJ Prime 4, so it's likely this project will remain a concept only.

[admin]

Detailed Review of New Chinese TFT Lossless Audio Decoding Module [Part 1]

It seems new versions of the Lossless Audio Decoding Modules mentioned above are coming out almost weekly. What follows is a detailed technical review of one version of these new 2.8 inch TFT Lossless Audio Decoding Modules.

For those wanting the top-down or "Pyramid Style" article, I'll start off by saying that these modules are very impressive for the cost. They are quite capable, the display is excellent, and the sound quality generally doesn't disappoint. Read on to get the details, and to see specifically why I had to caveat that last part.

Player_01.jpg (87.21 KiB) Viewed 9603 times

Photo from vendor product page on AliExpress. The players are available in Silver or Black.


Basics:
These players are strictly music players. While they have a very good 2.8" TFT full color screen, there is no effort to include Video, Photo, or eBook functionality. On start up, they briefly a splash screen showing the following:

WELCOME
--------------------
Music Player

This startup screen is in Blue, Green and orange, and is in a professional, modern font. No childish "Hello" message, and no Chinese.

After 3 seconds, the following Icons appear in a side scrolling format:

Music -- Bluetooth -- Line Input -- PC Mode -- System

Music:
As you may have guessed, this mode plays music from a USB storage device ("Thumb Drive") or from a MicroSD card (TF == "TransFlash"). To test sound quality, I made a simple JST connector-to-RCA adapter using one of the included 3 pin connectors, and plugged it into the audio out connector. Just a minor note on the connector: The included JST pigtail was wired so that the Yellow wire was the Right Channel, and the Red wire was Left. My own stash of JST plugs was wired the same way. This really is a nit, but generally speaking Red is used for the Right audio channel. Also, this would not be an issue using the included 1/8" (2.5mm) phone jack. I made the adapter this way so that I could use a stereo RCA patch cord to get me to the input of my Homemade 6BQ5 P-P Tube Amplifier. I have to say that these players really flattered me by making my Amp sound as good or better than it ever has. Yeah, I'm twisting this around to brag a little, but the point is that it sounded excellent end-to-end (maybe I should include my vintage Sony bookshelf speakers, too.)

DSC_0411_mod.JPG (245.39 KiB) Viewed 9598 times

Photo: Linuxslate.com. Note that the camera flash is causing the display to appear "washed out" the display is bright and crisp.

The screen during playback is also stylish and professional. A few notes, top to bottom:
1. An Icon on the top Left shows the basic mode. In Music Mode, the icon indicates if it is playing files from the USB drive or the SD Card (TF).
2. The Volume indication (Marked with a speaker icon) is covered in the above picture because the screen protection is still on. It indicates 30 volume steps.
3. Note indication of a FLAC format file being played, and I really like that it displays the file sample rate.
4. I do not know the meaning of the 1837/1439. There are approximately 1300 files and folders on the USB drive. If the intent is to show file playing out of total files, I would expect it to be the other way around. I will update this if I find out more.
5. Above the total track time is the Repeat Mode indicator. The following repeat modes are: All -- One -- Fol -- Ran. Unfortunately for use as a DJ player or Digital Turntable, there is no mode that stops after a track is played.
6. Large/cool looking time-in-track display, but there is no time remaining or a way to change this to time remaining, Total track time is shown on the right, and there is a smooth, clear position in track display.
7. The bottom part of the display is an audio Spectrum display, and I have to say that it is infinitely better than the rudimentary attempt in the player modules currently installed in the Poor Man's GoDJ. This display is fast, smooth, and actually represents the frequencies in the music. It is a summation of both channels, and does respond to the Volume and Equalizer settings. More on the Spectrum and waveform displays in the following sections and posts.

A few notes about selecting and playing songs -- and the only exception to the great sound: In Music mode, pressing the "Folder" button gets you to a basic file list. While I didn't specifically test it, I am quite sure the USB drive and the SD card can be used simultaneously. The file list is in relatively large white letters on black. It's easily visible, and fast. Scrolling is by the Right (Vol) encoder, and it basically goes as fast as you can turn the nob. Within the list, the filenames do not side scroll, so there is no way to see longer filenames. If your files all start with a long artist name, there's no way to tell them apart.

Now here's the biggest caveat to the sound quality: I tested this with the same USB drive I used in the original Poor Man's GoDJ, and that drive now has over 1300 songs on it (a 64G USB 3 Drive that is less than 1/2 full). While the scrolling is fast and smooth, scrolling quickly while playing a FLAC file results in the music hesitating and skipping significantly -- especially as you get further down the list of directories/files. I did not notice this while playing MP3 files. It happened with both 44.1 KB/s FLAC files and 48 KB/s FLAC files. This was the only time I heard the music skip or hesitate.

Songs are simply listed as they are on the storage device filesystem, (including the filesystem hierarchy). As with similar player modules, It ignores ID3 tags, and there are no options to sort or search.

Another big problem for some people will be the lack of support for Cyrillic (and likely other) fonts. Note in the picture above that the file playing is [blank].flac. The song playing has a Cyrillic name, so the Cyrillic characters are missing. Unless songs with Cyrillic names have a track number as part of the filename, it's impossible to tell what track you are selecting. This is true in the "Folder" list and on the Music Screen.

As mentioned and indicated on the panel, the Right encoder knob is the volume, and the Left encoder is goes to the next/previous track. Pressing the Right Encoder is Play/Pause as indicated on the panel, and pressing the Left encoder takes you back to the Icons screen while allowing the music to continue. (as opposed to pressing the Mode button, which abruptly stops the music and selects the next mode.) Long Pressing the right encoder seeks forward, and long pressing the Left seeks backwards. Seeking is responsive, but not smooth. It jumps in approx 5 second increments.

System:
I'm going to discuss the System "mode" or settings screen next. The settings are as follows, presented as Orange Text on a black background:
BackLight Time
BacklLight Brightness
EQ Settings
Language Select
Version
Quit

Most of these are self explanatory, but as this is a detailed description, I do want to discuss a few. As mentioned the screen is bright and clear. The default brightness setting is 90%, and this is generally fine. 100% may be selected in bright sunlight (such as in a vehicle, or portable player), and lower settings may be used in a darkened room. I don't really see the point of having the display timeout (it goes black, not dim) but perhaps in a battery powered situation, blanking the display would make sense. (see more about power consumption later.)

The unit shipped set to Traditional Chinese but it was relatively easy to just try each item until one of the settings has an option "english" (spelled out in English).

The next section will be dedicated to the EQ Settings, which is one of the most important and impressive aspects of this device.

[admin]

Detailed Review of New Chinese TFT Lossless Audio Decoding Module [Part 2]

The "EQ Setting", in the "System" panel, is one of the most important and impressive aspects of this device. When selected, the user is presented with a 10 Band Graphic Equalizer plus an overall gain control.

DSC_0416_mod.JPG (213.29 KiB) Viewed 9552 times

There are 7 presets: Normal - Rock - Pop - Classic - Jazz - Country - Bass and a Custom EQ. The selected EQ is retained, as are user settings under the "Custom" settings. There is no need to specifically save the Custom setting, and there is no way to have multiple Custom EQ settings. The pre-set settings cannot be modified. As with most of the UI, the EQ is nicely presented, and each band (and gain) of the Custom EQ can be set every DB. Using the Left and Right encoders to select the band and gain is fast and intuitive -- and since I'm an Audio Geek, I'll even say it's "fun".

So the EQ function looks nice, but how about the Sound? Well, I have to say that there is a night and day difference between this Module and other similar modules. Changes to the EQ chosen, or adjusting the "Custom" EQ is reflected in the sound immediately, and there is no loss of volume or fidelity. This unit is worth it's cost as a 10 band DSP EQ alone, and as we will see later it actually can be used this way. The EQ can be used in all modes, and really enhances the sound over a "flat" player.

Bluetooth:

The Bluetooth Device name is "Bluetooth Audio" (as apposed to some cryptic default chip ID). Pairing was immediate, and the unit appeared as the primary Audio Device under Linux (Using the pavucontrol audio control panel) without any further steps or setup. It was identified as "High Fidelity Audio Playback (A2DP Sink)" I played music from YouTube and it sounded as good as I would expect for a BT A2DP connection. The Volume Encoder controlled the PC volume and Pressing the Volume Encoder Paused the YT video as expected. In VLC, the Left Encoder wheel moved through the playing tracks, in addition to the above functionality. In Bluetooth mode, there was no information about the playing file. Only the name of the connected device was shown.

After I disconnected from the PC, I was able to connect via my Phone. It connected to Bluetooth Media only, not as a headset. There is no mic in this unit, and as mentioned it is intended as an audio device only. When playing a file from the phone, the Filename and ID3 information (if present in the file) was shown on the display. Scrolling through the files on my phone with the Left Wheel was immediate.

In one case, I played a file that apparently had only the artist name encoded in the ID3 tag. The Audio module displayed the Artist Name from the ID3 tag, and the Filename, but left the Album name and artist from a different track (and alblum/artist) on the screen. Minor Bugs like this are too be expected, and did not interfere with understanding what song was playing or the sound.

As with the Music app, the spectrum display is shown at the bottom, and was just as responsive.

As mentioned, the EQ works for the Bluetooth player, and with and A2DP connection, and the enhancement of the EQ, this becomes the best sounding BT connection I have ever heard.

The unit contains a typical PC board trace BT antenna and a tiny MHF style connector for a separate BT antenna, but no separate antenna or pigtail is provided.

As I write this, I am listening to Andromeda Dreams via this module and my Subminiature Tube PC speaker amp, and it sounds very nice.


Line Input:
The front panel includes a 1/8" (2.5mm) Phone (TRS) jack just above the USB connector. This allows the Sound TFT Lossless Audio Decoding Module to basically become a Pass-Thru Digital Signal Processor. As such, it has the following DSP audio functionality:

1. 30 Step DSP Volume Control (Including Remote Control)
2. DSP Graphic Equalizer as Outlined above.
3, DSP Audio Waveform Display
4. DSP Spectrum Display

As with the other Modes, the display is responsive and smooth. As with the Spectrum Display, the Waveform Display is nicely done, and in the style of professional audio equipment. However, it is not actually like the display on my Stanton SCS.4DJ or something like a Denon DJ PRIME 4+. First, the waveforms on equipment like that are made separately from the real-time playback. The "now" point of the playback is in or near the center, showing the DJ breaks, beats, etc. that are a few seconds into the future. Of course since this device is looking at the analog signal in real time, this is impossible. The "now" time is at the extreme right. Only the waveform that has already passed is shown. Secondly the color used in both the Waveform Display or the Spectrum are for appearance only. As the colors move from the greens to the yellow, orange and red, it does not actually mean much as far as 0 db, line level or the onset of distortion.

There is no noticeable lag or degradation of the sound to my ears, but of course the analog input signal is being sampled, quantized, processed, and then converted back to analog, filtered, buffered... etc. Right now, my friends over on the AudioKarma tube forums would be turning the same Orange and Red colors as the peaks of the Spectrum or Waveform displays at the thought of running a High Fidelity analog signal through such a device and then to a quality Tube Amplifier.

DSC_0409_mod.JPG (192.27 KiB) Viewed 9514 times

In this picture, 2 modules are connected together with a 1/8" TRS patch cord. The upper one is in Line Input Mode, and acting as just a Waveform Display.

I'd like to note that while there are inexpensive waveform display modules on various sites, This one is the only one in this price range that can provide this type of waveform display on a 2.8 inch screen.


PC Mode:
In PC Mode, the TFT Lossless Audio Decoding Module switches to essentially being a USB DAC, or USB "Sound Card". The USB "A" (Host) port becomes a USB device (peripheral) port. However, this isn't really "Legitimate" per the USB spec, and if the Audio Decoding Module is also powered from the rear Power connector, there is a chance that damage to a PC or other device could occur. There is a good post explaining this on Stack Exchange.

I'd also like to point out that "Real" USB DAC's have a USB -B or USB -C connector, or if they are configured as a USB-to audio adapter cable, they may include a fixed USB -A Male plug, all of which conform to the USB Specification.

That said, off brand Chinese products do this frequently, and as a result, I have one of the "evil" USB Male A to USB Male A cables on hand that came with my FNIRSI Digital Storage Scope.

**UPDATE** There seems to be an issue with these Modules in USB Audio Device mode. Please see details in the Following Post.

As with the Bluetooth Connection, the Player Module was immediately recognized and configured as the active USB sound device without me doing anything. This was tested on 2 different Linux PC's, each with a different Linux distribution. In addition to simply being a USB DAC, the module provides the same functionality as with Line In:

1. 30 Step DSP Volume Control (Including Remote Control)
2. DSP Graphic Equalizer as Outlined above.
3, DSP Audio Waveform Display
4. DSP Spectrum Display
... But it adds:
5. The Volume and Menu encoders become a USB HID (Human Interface Device) controller (Including Remote Control).
6. The TF Socket becomes a USB Card Reader.

I'll provide USB device details in a separate post, but as with Bluetooth, the expected functionality works. The Volume encoder controls the PC volume, and the Left knob works to select files if applicable to the PC application being used.

Since the USB sound spec does not have a provision for other data, filenames and ID3 information are not displayed. Unfortunately, the Player Module does not provide information about the sample rate of the incoming data.

While no one is saying that this is a professional or High Fidelity DAC, the fact that it includes a DSP Equalizer actually makes it sound better than a premium DAC without Equalization. Note that "Double Equalizing" by using a software Equalizer in the PC or playback device, and the Equalizer in the player module may give lots of highs and lows, it's not really making it Higher Fidelity or more accurate, even if it sounds "cool" to the untrained ear. With the Equalizer set to "Normal" (meaning flat), the sound was lower in volume, and definitely not as crisp when compared to a premium DAC that is built into my 6BQ5 Tube Amplifier.

It's not a premium DAC, but it does have a cool display,

Conclusion:
The 2.8" TFT Lossless Audio Decoding Module provides a lot of functionality, a cool display, and generally pretty good software for the price. I will definitely use at least a couple of the ones I bought to make a home and/or portable media player. The lack of a Single play and then stop "turntable" mode is a big factor that reduces the usefulness of this device as a player for a Poor Man's Go DJ 2.0.

Experimenting is fun, but I think I've finally learned that if you want a Denon DJ PRIME 4+, it's best to just buy a Denon DJ PRIME 4+.

[admin]

More^2 Technical Information on the " Chinese TFT Lossless Audio Decoding Module" [Part 3]

"More^2" isn't a typo. This is more (additional) information, and it is also more technical.

A few specifications:


Power:
The TFT Displays in the Color screen modules used in the Current Poor Man's GoDJ use significantly more power than the basic modules that it was originally built with. This presented challenges in the power supply design. So how do these modules stack up? Can they be used in a Battery powered device? Can they be powered from a continuous source of 12VDC in a car or boat without running down the battery?

The Unit described in this thread requires Regulated 5VDC source (USB or similar power supply). There is no "Battery" connection or voltage display.

Power off: 20 mA
Idle: 128 mA
Idle with USB drive inserted: 150 mA
Playing from USB drive: 200 mA

So this means approximately 10mA @12VDC when off if powered via a 12VDC to 5VDC Buck Converter. I'm rounding up, because Buck Converters are very efficient, but not 100% efficient. They may be more inefficient at very low loads (e.g. at 0 load, they are 100% inefficient). Also, if power is interrupted, the TFT Lossless Audio Decoding Modules return in a powered on state. An external method of isolation should be used in any application where these modules are powered from a battery, or situation were the power source may fluctuate or become intermittent.

Note also that if powered from the +5VDC Power connector, the Female USB-A connector will be a source of power at all times -- Even in "PC Mode". As mentioned in previously, this is a violation of the USB spec, and Damage to the USB Host port (PC) is possible.

A USB-A Male to USB-A Male cable should not be used to connect these Player Modules to a PC unless external power is disconnected.

If indented to be used as an external USB DAC (or USB "Sound Card"), a USB-B, USB-Micro or USB-C female connector should be correctly wired to the pins on he back of the USB-A female connector, and the 5VDC power connector on the back of the board should not be used.


USB Identification and End Points:

**UPDATE** See below for significant issues with these devices with Ubuntu 22.04.5 LTS and possibly other Linux Distributions. Since it is not known of this is an issue with the Linux drivers/or the Linux sound subsystems, It is not known at this time if these issues affect other platforms or not.

The output of lsusb -v for this device is pasted below. Here is a shortened summary.
Note our old friend Jieli Technology popping up again:


idVendor 0x4c4a
idProduct 0x4c55
bcdDevice 1.00
iManufacturer 1 Jieli Technology
iProduct 2 USB Composite Device

bInterfaceClass 8 Mass Storage

bInterfaceClass 1 Audio

bInterfaceClass 1 Audio

bInterfaceClass 1 Audio

bInterfaceClass 3 Human Interface Device


The 3 sound devices are:
Analog Stereo Output
Digital Stereo (IEC958) Output*
Off

*The unit does not have an IEC958 or any other digital output.

Code: Select all

Bus 001 Device 019: ID 4c4a:4c55 Jieli Technology USB Composite Device
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x4c4a 
  idProduct          0x4c55 
  bcdDevice            1.00
  iManufacturer           1 Jieli Technology
  iProduct                2 USB Composite Device
  iSerial                 3 433038393437372E
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x00ad
    bNumInterfaces          4
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         8 Mass Storage
      bInterfaceSubClass      6 SCSI
      bInterfaceProtocol     80 Bulk-Only
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         1
      bInterfaceCount         2
      bFunctionClass          1 Audio
      bFunctionSubClass       2 Streaming
      bFunctionProtocol       0 
      iFunction               5 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol      0 
      iInterface              5 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength       0x002f
        bInCollection           1
        baInterfaceNr(0)        2
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                10
        bDescriptorType        36
        bDescriptorSubtype      6 (FEATURE_UNIT)
        bUnitID                 2
        bSourceID               1
        bControlSize            1
        bmaControls(0)       0x01
          Mute Control
        bmaControls(1)       0x02
          Volume Control
        bmaControls(2)       0x02
          Volume Control
        iFeature                0 
      AudioControl Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      5 (SELECTOR_UNIT)
        bUnitID                 8
        bNrInPins               1
        baSourceID(0)           2
        iSelector               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0301 Speaker
        bAssocTerminal          0
        bSourceID               2
        iTerminal               0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           1
        bDelay                  1 frames
        wFormatTag         0x0001 PCM
      AudioStreaming Interface Descriptor:
        bLength                11
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             2
        bSubframeSize           3
        bBitResolution         24
        bSamFreqType            1 Discrete
        tSamFreq[ 0]        48000
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            9
          Transfer Type            Isochronous
          Synch Type               Adaptive
          Usage Type               Data
        wMaxPacketSize     0x0120  1x 288 bytes
        bInterval               1
        bRefresh                0
        bSynchAddress           0
        AudioStreaming Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x00
          bLockDelayUnits         0 Undefined
          wLockDelay         0x0000
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.00
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      51
         Report Descriptors: 
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               1

**UPDATE** There seems to be a serious issue when using these 2.8 inch TFT Lossless Audio Decoding Modules in USB Audio (USB Sound Card, or "PC Mode") on Current versions of Ubuntu Linux. It is not known if this is an issue with the modules themselves, or a Linux driver or Linux sound (ALSA) issue.

Again, for the search engines, we are talking about:
idVendor 0x4c4a
idProduct 0x4c55

iManufacturer 1 Jieli Technology
iProduct 2 USB Composite Device


Problem Descriptions:

Issue (1) After Playing sound for a while -- Usually a few minutes or about 1 song -- the sound will suddenly become a loud hiss. This occurs with any sound that is playing via USB -- Local files, YouTube, etc. The waveform and spectrum displays change -- i.e. no longer show the waveform/spectrum of music, but rather reflects the signal content of the hiss. The volume knob still works to control the volume of the hiss (fortunately). Normal functionality can be restored by unplugging and re-connecting the USB cable, or by switching between the sound outputs. The hiss returns after another few minutes of sound. This did not occur when the TFT Lossless Audio Decoding Module when plugged into an Android Device (Hacked Rabbit R1) after about 1/2 hour of playing music from YouTube.

Issue (2) Volume control does not work correctly in Analog Output Mode. In the regular Ubuntu Settings app, under Sound --> Output --> Balance, the Balance cannot be adjusted. Moving the slider Left produces no change. Moving the slider Right decreases the sound in both speakers, The waveform display continues to reflect only the change in the total volume. The sound is playing in stereo, and if balance is adjusted in the playing app, it behaves as expected. It is the output balance that cannot be controlled properly. The same thing happens when attempting to adjust the output balance using alsamixer, or pavucontrol. This seems to be an issue in the Linux sound sub system (ALSA or Pulse Audio.) There are other bug reports of similar issues with different devices that have the same USB Vendor/Product code and description.

Issue (3) As mentioned the device indicates a Digital Stereo (IEC958) Output, when in fact this module has no digital (S/PDIF) connection. If this output is chosen, volume control becomes basically unpredictable.

[admin]

You Wanna Make Something of It?! -- As a Matter of Fact, I do: New Chinese TFT Lossless Audio Decoding Module [Part 4]

While a Poor Man's GO DJ Version 2 is not being planned at this time, I am impressed overall with these modules, and wanted to build one as a stand alone player for my own use.

This is the result:

Completed player built into a bamboo organizer box

Player Module_mod_small.JPG (140.67 KiB) Viewed 34 times

A Target Store near me was selling a "Modular Bamboo Vanity Organizer" that consisted of a small tray, 2 small boxes and one larger box. Several of these seemed to have been removed from the packaging by people I am not proud to refer to as my "fellow shoppers". In one case all but one of the small boxes was missing, In another case, the packaging was torn, and the tray was broken, but all 3 boxes were present and intact. I asked at the service desk of they wanted to sell me any of the damaged merchandise at a reduced price. They gave me a discount, so I bought the set with the broken tray.

The small boxes were almost the perfect size for these player Modules.

Rear View of completed player

Player Module_back_small.JPG (150.68 KiB) Viewed 34 times